A pair of armrests are often associated with chairs to provide support for a users forearms while working despite the differences in sizes, shapes and preferences of users. This is particularly important for individuals having desk jobs where persons may stay seated for long periods of time and where different users use the same chair. It is also important for users that are different in size to be able to adjust the armrests to a lateral position that is comfortable for them. In this regard it is common for armrests to be selectively rotatable about a vertical axis.
For example, U.S. Pat. No. 5,769,496 relates to an adjustable arm apparatus including a lateral shaft having a stop member, an armrest frame rotatably mounted on the shaft allowing limited rotation and an actuator to act on the stop member to adjust the positioning and degree of rotation of the frame about the shaft.
Moreover, U.S. app. no. 2002/0070598 shows a swivel armrest providing the pivoting armrest to allow multi-position adjustment.
Furthermore U.S. Pat. No. 6,168,237 teaches an armrest construction for chairs which includes an armrest support having a lower end constructed for attachment to a chair, an upper end and a pivoting block attached to the upper end.
Furthermore U.S. Pat. No. 7,029,049 teaches an adjustable armrest and a method of inhibiting the movement of an armrest.
Finally, U.S. Pat. No. 6,948,775 relates to an armrest which includes a support rod, a base, a locating seat, a mounting seat and an upper cover wherein the base has a chamber having at least one guide rail, each provided with engagement grooves.
These and other prior art armrests present relatively complicated structures.
Furthermore it is not uncommon for a user to apply their weight against the armrests as the user rises from the chair. One of the difficulties experienced by prior art armrests resides in the instability which is exhibited during the application of force against the armrests when the user rises. It is not uncommon for these rotatable armrests to “give” and rotate unnecessarily during this action which can cause the user instability while rising.
In other words it is not uncommon for these armrests to rotate laterally outwardly from the chair, causing the users arms to move outwardly while rising. In other words, the rotatable armrests tend to laterally rotate about a vertical access of rotation.
Accordingly, there is a need to provide rotatable armrests which inhibit unwanted rotation while at the same time permitting rotation when the user is seated.